Newport Beach Police said a man suspected of fatally shooting a doctor was cooperating with investigators.

Authorities are continuing their investigation regarding the shooting death that occurred in the Hoag Health Center at 520 Superior Ave. at about 2:45 p.m. Monday.

Officers detained and arrested Stanwood Fred Elkus, 75, of Lake Elsinore, in connection to the shooting. Elkus was taken into custody without a struggle after officers found him in the room where the shooting took place.

Urologist Dr. Ronald Gilbert, 52, of Huntington Beach, was shot six to seven times in the torso in a patient exam room on the building's second floor. He was declared dead at the scene.

The entire medical office was put on lockdown in the moments after the shooting.

According to Kathy Lowe of the Newport Beach Police Department, Elkus has remained cooperative throughout the investigation. Lowe said officers searched Elkus's home late Monday night and found new evidence that might help uncover a motive. But as of Tuesday morning, the circumstances leading up to Gilbert's death remained unclear. Police did not immediately confirm whether Elkus was Gilbert's patient.

"It's going to be part of our ongoing investigation to determine the exact motive for this crime," Lowe said.

Newport Beach police would not elaborate on how the suspects knew each other but Gilbert's coworkers say Elkus was the doctor's longtime patient. Wednesday Matt Murphy, the prosecutor handling the case, said Elkus was not Gilbert's patient. Murphy said police were investigating whether Elkus was seeing any other doctors at Hoag Health Center.

"We have not received any complaints about Dr. Gilbert's care," Afable said. "He was, again, a very highly competent and a well-respected physician here. There are many people who are grieving."

Coworkers and friends described Gilbert as an all around good family man who was very involved with his synagogue and dedicated to helping the sickly.

Gilbert was a husband and a father of two. He was set to celebrate his 53rd birthday Wednesday.

Elkus is a retired barber. He lived in the same home in Lake Elsinore for 20 years. Neighbors described him as a friendly man who in recent years complained of prostate problems. He underwent surgery at least twice.

"He never really said whether it was a surgery that didn't work out, he just [said] don't ever go to the doctors for a prostate ever again," said neighbor Sherry Martin.

In a statement earlier Tuesday, Dr. Afable said: "The Hoag Hospital family is devastated by the senseless act of violence against Dr. Ronald Gilbert, our former chief of the Department of Urology who was on staff at the hospital for nearly 20 years," the statement read. "Dr. Gilbert dedicated his career to serving others. He was admired, respected and beloved by the Hoag family and will be deeply missed. Dr. Gilbert joined Hoag's staff on November 2, 1993 and served as the chair of the Urology Department from October 1998-September 2002."

The statement continued and sent condolences to Dr. Gilbert's family, staff, friends, patients, employees and medical staff.

Nurse Megan Mehan, an employee at the building, believes safety should be of utmost importance for hospitals now more than ever before. She suggested adopting medical detectors as a minimal safety measure.

UC Irvine medical student Brenton Alexander felt sympathy for both the suspect and the victim.

The aspiring premedical student said most physicians pursue an interest in the medical field because of their strong desire to help people.

"We like to deal with patients like this, the ones that are disturbed, the ones that need more time and care," he said. "That's probably the worst part of this is that we get in the field to deal with these people and they end up taking it back on us."

Elkus is being held on $1 million bail. He is scheduled to be arraigned on Wednesday.

Anyone with information regarding the shooting was asked to contact the Newport Beach Police Department at (800) 550-NBPD.